The present invention relates generally to wind power generation, and more particularly to a shaft brake mechanism of wind power generator.
In wind power generation, as the wind blows, the blades are driven to make the shaft of the generator rotate for converting kinetic energy into electrical energy. However, it is necessary to brake the shaft against rotation in some situations. Conventionally, an electromagnetic brake system is generally used to provide braking effect for the shaft. Such electromagnetic brake system must be continuously powered to keep providing braking effect or stop providing braking effect, allowing the shaft to rotate. As a result, a large amount of electrical energy is consumed for maintaining the function of such electromagnetic brake system.
Moreover, as shown in FIG. 10A, when a wind power generator operates in a condition that the rotational speed exceeds a nominal upper limit t1, the safety in operation will be threatened. Therefore, in the case that the wind speed exceeds a nominal upper limit t2 of wind speed and the rotational speed of the shaft reaches the nominal upper limit t1, it is necessary to stop the system. In this case, the total power generation capacity of the wind power generator will be reduced and the natural wind power resource can be hardly fully utilized to cause waste of resource.